import * as THREE from 'three';

class MeshLine extends THREE.BufferGeometry {
  constructor() {
    super();
    this.isMeshLine = true;
    this.type = 'MeshLine';

    this.positions = [];

    this.previous = [];
    this.next = [];
    this.side = [];
    this.width = [];
    this.indices_array = [];
    this.uvs = [];
    this.counters = [];
    this._points = [];
    this._geom = null;

    this.widthCallback = null;

    // Used to raycast
    this.matrixWorld = new THREE.Matrix4();

    Object.defineProperties(this, {
      // this is now a bufferGeometry
      // add getter to support previous api
      geometry: {
        enumerable: true,
        get: function () {
          return this;
        },
      },
      geom: {
        enumerable: true,
        get: function () {
          return this._geom;
        },
        set: function (value) {
          this.setGeometry(value, this.widthCallback);
        },
      },
      // for declaritive architectures
      // to return the same value that sets the points
      // eg. this.points = points
      // console.log(this.points) -> points
      points: {
        enumerable: true,
        get: function () {
          return this._points;
        },
        set: function (value) {
          this.setPoints(value, this.widthCallback);
        },
      },
    });
  }
}

MeshLine.prototype.setMatrixWorld = function (matrixWorld) {
  this.matrixWorld = matrixWorld;
};

// setting via a geometry is rather superfluous
// as you're creating a unecessary geometry just to throw away
// but exists to support previous api
MeshLine.prototype.setGeometry = function (g, c) {
  // as the input geometry are mutated we store them
  // for later retreival when necessary (declaritive architectures)
  this._geometry = g;
  this.setPoints(g.getAttribute('position').array, c);
};

MeshLine.prototype.setPoints = function (points, wcb) {
  if (!(points instanceof Float32Array) && !(points instanceof Array)) {
    console.error('ERROR: The BufferArray of points is not instancied correctly.');
    return;
  }
  // as the points are mutated we store them
  // for later retreival when necessary (declaritive architectures)
  this._points = points;
  this.widthCallback = wcb;
  this.positions = [];
  this.counters = [];
  if (points.length && points[0] instanceof THREE.Vector3) {
    // could transform Vector3 array into the array used below
    // but this approach will only loop through the array once
    // and is more performant
    for (var j = 0; j < points.length; j++) {
      let p = points[j];
      var c = j / points.length;
      this.positions.push(p.x, p.y, p.z);
      this.positions.push(p.x, p.y, p.z);
      this.counters.push(c);
      this.counters.push(c);
    }
  } else {
    for (var j = 0; j < points.length; j += 3) {
      var c = j / points.length;
      this.positions.push(points[j], points[j + 1], points[j + 2]);
      this.positions.push(points[j], points[j + 1], points[j + 2]);
      this.counters.push(c);
      this.counters.push(c);
    }
  }
  this.process();
};

function MeshLineRaycast(raycaster, intersects) {
  let inverseMatrix = new THREE.Matrix4();
  let ray = new THREE.Ray();
  let sphere = new THREE.Sphere();
  let interRay = new THREE.Vector3();
  let geometry = this.geometry;
  // Checking boundingSphere distance to ray

  if (!geometry.boundingSphere) geometry.computeBoundingSphere();
  sphere.copy(geometry.boundingSphere);
  sphere.applyMatrix4(this.matrixWorld);

  if (raycaster.ray.intersectSphere(sphere, interRay) === false) {
    return;
  }

  inverseMatrix.copy(this.matrixWorld).invert();
  ray.copy(raycaster.ray).applyMatrix4(inverseMatrix);

  let vStart = new THREE.Vector3();
  let vEnd = new THREE.Vector3();
  let interSegment = new THREE.Vector3();
  let step = this instanceof THREE.LineSegments ? 2 : 1;
  let index = geometry.index;
  let attributes = geometry.attributes;

  if (index !== null) {
    let indices = index.array;
    let positions = attributes.position.array;
    let widths = attributes.width.array;

    for (let i = 0, l = indices.length - 1; i < l; i += step) {
      let a = indices[i];
      let b = indices[i + 1];

      vStart.fromArray(positions, a * 3);
      vEnd.fromArray(positions, b * 3);
      let width = widths[Math.floor(i / 3)] !== undefined ? widths[Math.floor(i / 3)] : 1;
      let precision = raycaster.params.Line.threshold + (this.material.lineWidth * width) / 2;
      let precisionSq = precision * precision;

      let distSq = ray.distanceSqToSegment(vStart, vEnd, interRay, interSegment);

      if (distSq > precisionSq) continue;

      interRay.applyMatrix4(this.matrixWorld); // Move back to world space for distance calculation

      let distance = raycaster.ray.origin.distanceTo(interRay);

      if (distance < raycaster.near || distance > raycaster.far) continue;

      intersects.push({
        distance: distance,
        // What do we want? intersection point on the ray or on the segment??
        // point: raycaster.ray.at( distance ),
        point: interSegment.clone().applyMatrix4(this.matrixWorld),
        index: i,
        face: null,
        faceIndex: null,
        object: this,
      });
      // make event only fire once
      i = l;
    }
  }
}
MeshLine.prototype.raycast = MeshLineRaycast;
MeshLine.prototype.compareV3 = function (a, b) {
  let aa = a * 6;
  let ab = b * 6;
  return (
    this.positions[aa] === this.positions[ab] &&
    this.positions[aa + 1] === this.positions[ab + 1] &&
    this.positions[aa + 2] === this.positions[ab + 2]
  );
};

MeshLine.prototype.copyV3 = function (a) {
  let aa = a * 6;
  return [this.positions[aa], this.positions[aa + 1], this.positions[aa + 2]];
};

MeshLine.prototype.process = function () {
  let l = this.positions.length / 6;

  this.previous = [];
  this.next = [];
  this.side = [];
  this.width = [];
  this.indices_array = [];
  this.uvs = [];

  let w;

  let v;
  // initial previous points
  if (this.compareV3(0, l - 1)) {
    v = this.copyV3(l - 2);
  } else {
    v = this.copyV3(0);
  }
  this.previous.push(v[0], v[1], v[2]);
  this.previous.push(v[0], v[1], v[2]);

  for (let j = 0; j < l; j++) {
    // sides
    this.side.push(1);
    this.side.push(-1);

    // widths
    if (this.widthCallback) w = this.widthCallback(j / (l - 1));
    else w = 1;
    this.width.push(w);
    this.width.push(w);

    // uvs
    this.uvs.push(j / (l - 1), 0);
    this.uvs.push(j / (l - 1), 1);

    if (j < l - 1) {
      // points previous to poisitions
      v = this.copyV3(j);
      this.previous.push(v[0], v[1], v[2]);
      this.previous.push(v[0], v[1], v[2]);

      // indices
      let n = j * 2;
      this.indices_array.push(n, n + 1, n + 2);
      this.indices_array.push(n + 2, n + 1, n + 3);
    }
    if (j > 0) {
      // points after poisitions
      v = this.copyV3(j);
      this.next.push(v[0], v[1], v[2]);
      this.next.push(v[0], v[1], v[2]);
    }
  }

  // last next point
  if (this.compareV3(l - 1, 0)) {
    v = this.copyV3(1);
  } else {
    v = this.copyV3(l - 1);
  }
  this.next.push(v[0], v[1], v[2]);
  this.next.push(v[0], v[1], v[2]);

  // redefining the attribute seems to prevent range errors
  // if the user sets a differing number of vertices
  if (!this._attributes || this._attributes.position.count !== this.positions.length) {
    this._attributes = {
      position: new THREE.BufferAttribute(new Float32Array(this.positions), 3),
      previous: new THREE.BufferAttribute(new Float32Array(this.previous), 3),
      next: new THREE.BufferAttribute(new Float32Array(this.next), 3),
      side: new THREE.BufferAttribute(new Float32Array(this.side), 1),
      width: new THREE.BufferAttribute(new Float32Array(this.width), 1),
      uv: new THREE.BufferAttribute(new Float32Array(this.uvs), 2),
      index: new THREE.BufferAttribute(new Uint16Array(this.indices_array), 1),
      counters: new THREE.BufferAttribute(new Float32Array(this.counters), 1),
    };
  } else {
    this._attributes.position.copyArray(new Float32Array(this.positions));
    this._attributes.position.needsUpdate = true;
    this._attributes.previous.copyArray(new Float32Array(this.previous));
    this._attributes.previous.needsUpdate = true;
    this._attributes.next.copyArray(new Float32Array(this.next));
    this._attributes.next.needsUpdate = true;
    this._attributes.side.copyArray(new Float32Array(this.side));
    this._attributes.side.needsUpdate = true;
    this._attributes.width.copyArray(new Float32Array(this.width));
    this._attributes.width.needsUpdate = true;
    this._attributes.uv.copyArray(new Float32Array(this.uvs));
    this._attributes.uv.needsUpdate = true;
    this._attributes.index.copyArray(new Uint16Array(this.indices_array));
    this._attributes.index.needsUpdate = true;
  }

  this.setAttribute('position', this._attributes.position);
  this.setAttribute('previous', this._attributes.previous);
  this.setAttribute('next', this._attributes.next);
  this.setAttribute('side', this._attributes.side);
  this.setAttribute('width', this._attributes.width);
  this.setAttribute('uv', this._attributes.uv);
  this.setAttribute('counters', this._attributes.counters);

  this.setIndex(this._attributes.index);

  this.computeBoundingSphere();
  this.computeBoundingBox();
};

function memcpy(src, srcOffset, dst, dstOffset, length) {
  let i;

  src = src.subarray || src.slice ? src : src.buffer;
  dst = dst.subarray || dst.slice ? dst : dst.buffer;

  src = srcOffset
    ? src.subarray
      ? src.subarray(srcOffset, length && srcOffset + length)
      : src.slice(srcOffset, length && srcOffset + length)
    : src;

  if (dst.set) {
    dst.set(src, dstOffset);
  } else {
    for (i = 0; i < src.length; i++) {
      dst[i + dstOffset] = src[i];
    }
  }

  return dst;
}

/**
 * Fast method to advance the line by one position.  The oldest position is removed.
 * @param position
 */
MeshLine.prototype.advance = function (position) {
  let positions = this._attributes.position.array;
  let previous = this._attributes.previous.array;
  let next = this._attributes.next.array;
  let l = positions.length;

  // PREVIOUS
  memcpy(positions, 0, previous, 0, l);

  // POSITIONS
  memcpy(positions, 6, positions, 0, l - 6);

  positions[l - 6] = position.x;
  positions[l - 5] = position.y;
  positions[l - 4] = position.z;
  positions[l - 3] = position.x;
  positions[l - 2] = position.y;
  positions[l - 1] = position.z;

  // NEXT
  memcpy(positions, 6, next, 0, l - 6);

  next[l - 6] = position.x;
  next[l - 5] = position.y;
  next[l - 4] = position.z;
  next[l - 3] = position.x;
  next[l - 2] = position.y;
  next[l - 1] = position.z;

  this._attributes.position.needsUpdate = true;
  this._attributes.previous.needsUpdate = true;
  this._attributes.next.needsUpdate = true;
};

THREE.ShaderChunk['meshline_vert'] = [
  '',
  THREE.ShaderChunk.logdepthbuf_pars_vertex,
  THREE.ShaderChunk.fog_pars_vertex,
  '',
  'attribute vec3 previous;',
  'attribute vec3 next;',
  'attribute float side;',
  'attribute float width;',
  'attribute float counters;',
  '',
  'uniform vec2 resolution;',
  'uniform float lineWidth;',
  'uniform vec3 color;',
  'uniform float opacity;',
  'uniform float sizeAttenuation;',
  '',
  'varying vec2 vUV;',
  'varying vec4 vColor;',
  'varying float vCounters;',
  '',
  'vec2 fix( vec4 i, float aspect ) {',
  '',
  '    vec2 res = i.xy / i.w;',
  '    res.x *= aspect;',
  '	 vCounters = counters;',
  '    return res;',
  '',
  '}',
  '',
  'void main() {',
  '',
  '    float aspect = resolution.x / resolution.y;',
  '',
  '    vColor = vec4( color, opacity );',
  '    vUV = uv;',
  '',
  '    mat4 m = projectionMatrix * modelViewMatrix;',
  '    vec4 finalPosition = m * vec4( position, 1.0 );',
  '    vec4 prevPos = m * vec4( previous, 1.0 );',
  '    vec4 nextPos = m * vec4( next, 1.0 );',
  '',
  '    vec2 currentP = fix( finalPosition, aspect );',
  '    vec2 prevP = fix( prevPos, aspect );',
  '    vec2 nextP = fix( nextPos, aspect );',
  '',
  '    float w = lineWidth * width;',
  '',
  '    vec2 dir;',
  '    if( nextP == currentP ) dir = normalize( currentP - prevP );',
  '    else if( prevP == currentP ) dir = normalize( nextP - currentP );',
  '    else {',
  '        vec2 dir1 = normalize( currentP - prevP );',
  '        vec2 dir2 = normalize( nextP - currentP );',
  '        dir = normalize( dir1 + dir2 );',
  '',
  '        vec2 perp = vec2( -dir1.y, dir1.x );',
  '        vec2 miter = vec2( -dir.y, dir.x );',
  '        //w = clamp( w / dot( miter, perp ), 0., 4. * lineWidth * width );',
  '',
  '    }',
  '',
  '    //vec2 normal = ( cross( vec3( dir, 0. ), vec3( 0., 0., 1. ) ) ).xy;',
  '    vec4 normal = vec4( -dir.y, dir.x, 0., 1. );',
  '    normal.xy *= .5 * w;',
  '    normal *= projectionMatrix;',
  '    if( sizeAttenuation == 0. ) {',
  '        normal.xy *= finalPosition.w;',
  '        normal.xy /= ( vec4( resolution, 0., 1. ) * projectionMatrix ).xy;',
  '    }',
  '',
  '    finalPosition.xy += normal.xy * side;',
  '',
  '    gl_Position = finalPosition;',
  '',
  THREE.ShaderChunk.logdepthbuf_vertex,
  THREE.ShaderChunk.fog_vertex && '    vec4 mvPosition = modelViewMatrix * vec4( position, 1.0 );',
  THREE.ShaderChunk.fog_vertex,
  '}',
].join('\n');

THREE.ShaderChunk['meshline_frag'] = [
  '',
  THREE.ShaderChunk.fog_pars_fragment,
  THREE.ShaderChunk.logdepthbuf_pars_fragment,
  '',
  'uniform sampler2D map;',
  'uniform sampler2D alphaMap;',
  'uniform float useMap;',
  'uniform float useAlphaMap;',
  'uniform float useDash;',
  'uniform float dashArray;',
  'uniform float dashOffset;',
  'uniform float dashRatio;',
  'uniform float visibility;',
  'uniform float alphaTest;',
  'uniform vec2 repeat;',
  'uniform vec2 mapOffset;',
  '',
  'varying vec2 vUV;',
  'varying vec4 vColor;',
  'varying float vCounters;',
  '',
  'void main() {',
  '',
  THREE.ShaderChunk.logdepthbuf_fragment,
  '',
  '    vec4 c = vColor;',
  '    if( useMap == 1. ) c *= texture2D( map, (vUV + mapOffset) * repeat );',
  '    if( useAlphaMap == 1. ) c.a *= texture2D( alphaMap, vUV * repeat ).a;',
  '    if( c.a < alphaTest ) discard;',
  '    if( useDash == 1. ){',
  '        c.a *= ceil(mod(vCounters + dashOffset, dashArray) - (dashArray * dashRatio));',
  '    }',
  '    gl_FragColor = c;',
  '    gl_FragColor.a *= step(vCounters, visibility);',
  '',
  THREE.ShaderChunk.fog_fragment,
  '}',
].join('\n');

class MeshLineMaterial extends THREE.ShaderMaterial {
  constructor(parameters) {
    super({
      uniforms: {
        ...THREE.UniformsLib.fog,
        lineWidth: { value: 1 },
        map: { value: null },
        useMap: { value: 0 },
        alphaMap: { value: null },
        useAlphaMap: { value: 0 },
        color: { value: new THREE.Color(0xffffff) },
        opacity: { value: 1 },
        resolution: { value: new THREE.Vector2(1, 1) },
        sizeAttenuation: { value: 1 },
        dashArray: { value: 0 },
        dashOffset: { value: 0 },
        dashRatio: { value: 0.5 },
        useDash: { value: 0 },
        visibility: { value: 1 },
        alphaTest: { value: 0 },
        repeat: { value: new THREE.Vector2(1, 1) },
        mapOffset: { value: new THREE.Vector2(0, 0) },
      },

      vertexShader:
        `
        bool isPerspectiveMatrix(mat4) {
            return true;
        }
    ` + THREE.ShaderChunk.meshline_vert,

      fragmentShader: THREE.ShaderChunk.meshline_frag,
    });
    this.isMeshLineMaterial = true;
    this.type = 'MeshLineMaterial';

    Object.defineProperties(this, {
      lineWidth: {
        enumerable: true,
        get: function () {
          return this.uniforms.lineWidth.value;
        },
        set: function (value) {
          this.uniforms.lineWidth.value = value;
        },
      },
      map: {
        enumerable: true,
        get: function () {
          return this.uniforms.map.value;
        },
        set: function (value) {
          this.uniforms.map.value = value;

          // relate attribute
          this.uniforms.useMap.value = Boolean(value);
          this.uniforms.mapOffset.value = value?.offset;
        },
      },
      useMap: {
        enumerable: true,
        get: function () {
          return this.uniforms.useMap.value;
        },
        set: function (value) {
          this.uniforms.useMap.value = value;
        },
      },
      alphaMap: {
        enumerable: true,
        get: function () {
          return this.uniforms.alphaMap.value;
        },
        set: function (value) {
          this.uniforms.alphaMap.value = value;
        },
      },
      useAlphaMap: {
        enumerable: true,
        get: function () {
          return this.uniforms.useAlphaMap.value;
        },
        set: function (value) {
          this.uniforms.useAlphaMap.value = value;
        },
      },
      color: {
        enumerable: true,
        get: function () {
          return this.uniforms.color.value;
        },
        set: function (value) {
          this.uniforms.color.value = value;
        },
      },
      opacity: {
        enumerable: true,
        get: function () {
          return this.uniforms.opacity.value;
        },
        set: function (value) {
          this.uniforms.opacity.value = value;
        },
      },
      resolution: {
        enumerable: true,
        get: function () {
          return this.uniforms.resolution.value;
        },
        set: function (value) {
          this.uniforms.resolution.value.copy(value);
        },
      },
      sizeAttenuation: {
        enumerable: true,
        get: function () {
          return this.uniforms.sizeAttenuation.value;
        },
        set: function (value) {
          this.uniforms.sizeAttenuation.value = value;
        },
      },
      dashArray: {
        enumerable: true,
        get: function () {
          return this.uniforms.dashArray.value;
        },
        set: function (value) {
          this.uniforms.dashArray.value = value;
          this.useDash = value !== 0 ? 1 : 0;
        },
      },
      dashOffset: {
        enumerable: true,
        get: function () {
          return this.uniforms.dashOffset.value;
        },
        set: function (value) {
          this.uniforms.dashOffset.value = value;
        },
      },
      dashRatio: {
        enumerable: true,
        get: function () {
          return this.uniforms.dashRatio.value;
        },
        set: function (value) {
          this.uniforms.dashRatio.value = value;
        },
      },
      useDash: {
        enumerable: true,
        get: function () {
          return this.uniforms.useDash.value;
        },
        set: function (value) {
          this.uniforms.useDash.value = value;
        },
      },
      visibility: {
        enumerable: true,
        get: function () {
          return this.uniforms.visibility.value;
        },
        set: function (value) {
          this.uniforms.visibility.value = value;
        },
      },
      alphaTest: {
        enumerable: true,
        get: function () {
          return this.uniforms.alphaTest.value;
        },
        set: function (value) {
          this.uniforms.alphaTest.value = value;
        },
      },
      repeat: {
        enumerable: true,
        get: function () {
          return this.uniforms.repeat.value;
        },
        set: function (value) {
          this.uniforms.repeat.value.copy(value);
        },
      },
      mapOffset: {
        enumerable: true,
        get: function () {
          return this.uniforms.mapOffset.value;
        },
        set: function (value) {
          this.uniforms.mapOffset.value = value;
        },
      },
    });

    this.setValues(parameters);
  }
}

MeshLineMaterial.prototype.copy = function (source) {
  THREE.ShaderMaterial.prototype.copy.call(this, source);

  this.lineWidth = source.lineWidth;
  this.map = source.map;
  this.useMap = source.useMap;
  this.alphaMap = source.alphaMap;
  this.useAlphaMap = source.useAlphaMap;
  this.color.copy(source.color);
  this.opacity = source.opacity;
  this.resolution.copy(source.resolution);
  this.sizeAttenuation = source.sizeAttenuation;
  this.dashArray.copy(source.dashArray);
  this.dashOffset.copy(source.dashOffset);
  this.dashRatio.copy(source.dashRatio);
  this.useDash = source.useDash;
  this.visibility = source.visibility;
  this.alphaTest = source.alphaTest;
  this.repeat.copy(source.repeat);

  return this;
};

export { MeshLine, MeshLineMaterial, MeshLineRaycast };
